Journals / Turkish Journal of Chemistry / 2010 / Cilt: 34 - Sayı: 5
Effect of various substituents on intramolecular 1,1-vinylboration, synthesis of 1-silacyclobutene derivatives
- Journal
- Turkish Journal of Chemistry
- Pages
- 793–803
- DOI
- —
Abstract
The reaction of 1-boryl-1-alkenyl chlorosilane derivatives with alkynyllithium reagents [Li-C\equiv C-R3 (R3~=~Ph, SiMe3)] at low temperature (--78 °C) affords alkenyl(alkyn-1-yl)silanes. These compounds are precursors of 1-silacyclobutene derivatives, which are formed via intramolecular 1,1-vinylboration. This reaction works for various groups at silicon (R1/R2: R1 = H, Me, Ph; R2 = Me, Ph) and at the C=C and C\equiv C units (R/R3: R = nBu, Ph; R3 = nBu, Ph, SiMe3). The conversion into 1-silacyclobutene derivatives is incomplete only in the case of R3 = SiMe3. The reactions were monitored by NMR spectroscopy in order to elucidate the reaction mechanism, and the proposed structures of all new compounds follow from consistent sets of NMR parameters (1H-, 13C-, 11B-, 29Si-NMR).
Özet
The reaction of 1-boryl-1-alkenyl chlorosilane derivatives with alkynyllithium reagents [Li-C\equiv C-R3 (R3~=~Ph, SiMe3)] at low temperature (--78 °C) affords alkenyl(alkyn-1-yl)silanes. These compounds are precursors of 1-silacyclobutene derivatives, which are formed via intramolecular 1,1-vinylboration. This reaction works for various groups at silicon (R1/R2: R1 = H, Me, Ph; R2 = Me, Ph) and at the C=C and C\equiv C units (R/R3: R = nBu, Ph; R3 = nBu, Ph, SiMe3). The conversion into 1-silacyclobutene derivatives is incomplete only in the case of R3 = SiMe3. The reactions were monitored by NMR spectroscopy in order to elucidate the reaction mechanism, and the proposed structures of all new compounds follow from consistent sets of NMR parameters (1H-, 13C-, 11B-, 29Si-NMR).